1. Field of the Invention
This invention relates in general to an electrophotographic element, and in particular to a novel electrophotographic element having a photosensitive layer containing a disazo as an pigment active ingredient.
2. Description of the Prior Art
As electrophotographic elements of such a type that comprises an electrically conductive support and a photosensitive layer, superposed thereon, containing an azo pigment as an active ingredient, there have hitherto been known, for instance, the electrophotographic element using a monoazo pigment (Japanese Patent Publication No. 16474/1969), or using a benzidine type disazo pigment (Japanese Laid-open Patent Application No. 37543/1972) and so forth. It is admitted that these azo pigments are, as above mentioned, serviceable as the active ingredient for the photosensitive layer. In spite of this, the fact is that no azo pigment has yet been obtained which can fully satisfy various demands of electrophotographic processes. Taking this fact into consideration, therefore, it is desirable to extend the range of pigments so that one may select pigments operable as active ingredients from within a wide range without being restricted only to azo pigments. Otherwise, it will not be possible to provide an electrophotographic element which is substantially suitable for a certain process. In other words, it is preferable in the electrophotographic process that the pigments operable as active ingredients are of as many different kinds as possible.